Increased demand for cleaner fuel due to environmental concern and depleting petroleum reserves in the world coupled with deteriorating quality of the crude oil have led a surge of research for renewable and clean fuel sources. One of the renewable sources may be the oil originating from vegetables and animals such as waste restaurant oil, soyabean oil, jatropha oil, and algae oil etc. This also helps in rural development by providing better cost for their products. But these oils originating from vegetables and animals cannot be used directly in the engine or in the petrochemical complexes as feed stocks, due to the problems inherent with these oils such as higher viscosity and oxygen content and poor atomization and lubricity. Therefore before using in the engine or in the petrochemical complexes these oils are to be converted into bio-diesel or green diesel or aromatic rich feed stocks. Bio-diesel which is Fatty Acid Methyl Esters (FAME) is produced by transesterification of fatty acids in triglycerides. To use bio-diesel in the engine requires some modification and additional disadvantages are poor performance in cold weather and poor emission. One way of effectively using these renewable oils is by converting these oils into hydrocarbons with much higher cetane value than conventional diesel fuel, another way is by converting these oils to aromatic rich feedstock along with cracked, isomerized, cyclized products which would be even more valuable than the diesel range hydrocarbons. This process involves conversion of glycerides and fatty acids in renewable oils into C1-C24 hydrocarbon compounds and requires H2 gas as an input gas. Hydrogen is consumed during the process due to hydrodeoxygenation, decarbonylation, decarboxylation, isomerisation, hydrocracking reactions. The consumption of hydrogen gas during the process makes the process difficult to be operated in a standalone operation mode and requires an additional H2 source from refineries for conversion of these oils. This additional requirement of hydrogen makes the process economically less attractive and increases the dependence of this developed technology on refineries or at places where there are existing H2 production facilities.
The patented literature presents some documents in the hydrogenation of vegetable oil, and some for producing hydrogen from triglycerides using steam reforming at extensively high temperatures 550° C. and above but these documents do not consider in their scope the intended process, methods and systems described by this invention.
U.S. Pat. No. 8,147,766 B2 and U.S. Pat. No. 7,960,598 B2 discloses in one embodiment of the invention a steam reforming unit for processing biomass derived oil specifically triglycerides by steam-reforming to yield bio-derived H2. The patent document also discloses co-reforming a portion of the monoesters with the triglycerides sequentially in the same unit or in parallel in a different unit. The steam-reforming reactions occur at very high temperatures between 550° C.-880° C. as explained in the detailed description section of the disclosed invention (Column 6, lines 12-14). These extremely high temperatures lead to catalyst deactivation and need catalyst regeneration for maintaining catalyst activity.
U.S. Pat. No. 2,163,563 discloses the hydrogenation of vegetable oils combined with mineral oil over a reduced Ni catalyst supported in alumina in the presence of hydrogen at high pressure [5 MPa to 50.6 MPa (50 to 500 atmospheres)]. However, this patent does not involve hydrotreatment of a combined load of petroleum and vegetable oils through an HDT process. U.S. Pat. No. 4,300,009 describes a process for generating the product having the boiling point at the range of gasoline boiling point range. This process involves catalytic conversion of anabolites (substances formed in the anabolic process) as resins, vegetable oils and fats in liquid hydrocarbons over zeolites with an effective pore size bigger than 5 Angstrom. U.S. Pat. No. 5,705,722 describes a process to produce additives for diesel fuel which have higher cetane number and may improve ignition of the fuel. The process involves hydroprocessing of the biomass, containing a high proportion of unsaturated fatty acids, wood oils, animal fats and other mixtures in the presence of hydrogen over catalyst. This mixture is then separated and fractioned to obtain a hydrocarbon product with boiling point at the range of diesel's boiling point, being this product the additive with a high cetane number. However the addition of a petroleum hydrocarbon to the biomass load which is being hydroprocessed is not mentioned within this document.
U.S. Pat. No. 4,992,605 describes a process to obtain a stream with a high cetane number to be added to the diesel in the refinery. The process involves hydroprocessing of vegetable oils such as canola or sunflower oil, palm and wood oil that is a waste product from the wood pulp industry, to produce hydrocarbon products in the diesel boiling range by using sulfided catalyst (NiMo and CoMo) in the presence of hydrogen (pressure of 4 to 15 MPa) and temperature in the range of 350° C. to 450° C. This patent does not consider a mixture of a hydrocarbon with vegetable oil in the hydrorefining.
U.S. Pat. Nos. 7,491,858, 7,459,597 B2 describe production of diesel fuel from vegetable and animal oils and also the further isomerization of obtained hydrocarbons using catalysts known in the prior art. Patent WO2008054442 describes a process for converting triglycerides to hydrocarbons. U.S. Pat. No. 4,300,009 describe the production of hydrocarbons such as gasoline and chemicals such as para-xylene from plant oils such as corn oil by using of crystalline aluminosilicate zeolites. US 2004/0230085 A1 discloses a process for treating a hydrocarbon component of biological origin by hydrodeoxygenation followed by isomerization.
WO 2009/039000, WO 2009/039335, WO/2009/039347 describe a process which comprises one or more steps to hydrogenate, decarboxylate, decarbonylate, (and/or hydrodeoxygenate) and isomerize the renewable feedstock, the consumption of hydrogen in the deoxygenation reaction zone is reduced by using at least one sulfur containing component which also operates to maintain the catalyst in a sulfided state.
Our other patent application numbers 3039/DEL/2012, WO 2014/049621, 3441/DEL/2012, 2622/DEL/2014 disclose formation of biofuels and aromatics from lipids, but these inventions do not disclose the production of hydrogen along with hydrocarbons.
In spite of these developments, there is no evidence in literature for low temperature (250-500° C.) hydrogen production along with hydrocarbons from glycerides catalytically using simultaneous combination of hydroconversion, reforming and water gas shift reactions. There is a need for development of a catalyst and process which can be economical and can be operated on a standalone basis for the conversion of glycerides and fatty acids from plant, animal or algae oil without any overall hydrogen requirement for the process.